The field of the disclosure described herein relates generally to monitoring gas turbine engine systems, and more specifically, to methods and systems for controlling combustion emission parameters in a combustion system.
Industrial gas turbines often require complex control systems for efficiently converting energy while minimizing polluting emissions. Pollutants such as nitrogen oxide may be reduced by lowering the maximum gas temperature, which may be achieved by maintaining a lean fuel-to-air ratio in the combustion chamber. However, if the fuel/air mixture is too lean, incomplete fuel combustion can produce excessive carbon monoxide and unburned hydrocarbons.
At least some known control systems attempt to control the fuel/air mixture by measuring various combustion parameters, and by using the measurements as input to control the fuel system. For example, one known control system receives fuel flow rates, pressure levels, and discharge exhaust temperature distributions as input for setting fuel trim control valves. The control system uses such data and attempts to optimize operation of the gas turbine assembly. However, the effectiveness of such systems may be limited by the effectiveness of the sensors and such control systems may require separate and redundant sensors for determining each parameter. As such, the benefits gained from such systems may be offset or limited by the cost and effectiveness of the sensors.